1. Field of the Invention
The invention relates to a mechanism for locking the steering fins of a missile in place when the missile is not in use. The mechanism immobilizes the output shafts of the missile steering fins and is disengaged when the missile is ready for launch.
2. Description of the Related Art
U.S. Pat. No. 5,505,408 to John M. Speicher, Allan A. Voigt and Che-Ram S. Voigt, assigned to the same assignee as the present invention, shows a missile control system which effects steering of a missile using rotatable fins. The disclosure of that patent is incorporated herein by reference. In that disclosure, relying on dynamic pressure, pairs of fins disposed on opposite sides of a missile are rotated in unison to achieve yaw and pitch motion and in opposition to achieve roll motion during flight. The fins are rotated by output shafts to which they are connected, which output shafts extend into the missile and engage corresponding actuator motors via associated gear linkages. The motors are responsive to command signals issued by the missile autopilot and thereby effect steering control of the missile.
The steering fins of a missile are critical components whose proper function is crucial to the navigation and stability of the craft. Accurate flight of the missile depends on precise alignment of these components, and reducing their susceptibility to mis-alignment during pre-flight handling of the missile is important.
Locking the missile fins in place when the missile is not in use reduces the possibility of mis-alignment and wear on the missile fins and related components. Moreover, such immobilization of the missile fins facilitates pre-flight handling of the missile. Another important reason for locking the fins is to prevent damage to the actuator during air carry when the missile is carried external to the aircraft. Aerodynamic loads resulting from high speed flight could cause the fins to move which in turn might damage the actuator or the aircraft. A light weight, simple device for this purpose, which has a minimal number of moving parts and which is readily and simultaneously disengageable from all the fins, would therefore improve missile reliability and performance.